[P2-180] Clinical and genetic analysis of 124 Chinese patients with hypomyelinating leukodystrophies
[Objective]To analyze the clinical and genetic characteristics of Chinese HLD patients. [Method] Patients with developmental delay and hypomyelinating change in brain MRI in our clinic from Sep, 2005 to Nov, 2014 are collected. [Results]124 patients have been diagnosed HLDs clinically, including 95 PMD (95/124, 76.61%), 12 PMLD (Pelizaeus-Merzbacher-like disease, 12/124, 9.68%), 7 GM1/GM2 gangliosidosis (7/124, 5.64%), and other rare diseases such as H-ABC, Sjogren-Larsson syndrome, SPG-35, trichothiodystrophy, MSUD (Maple syrup urine disease), NCL (Neuronal Ceroid Lipofuscinosis) and 18q deletion syndrome. Development delay and nystagmus are among the most often seen symptoms, while clinical examinations and brain MRI have provided important help for diagnosis. Among them 113 patients are found gene mutation or chromosome change. Meanwhile, molecular diagnosis of left patients are unknown (11/124, 8.87%). The genes with mutations include PLP1 (89/113, 78.76%), GJC2 (9/113, 7.96%), GLB1 (5/113, 4.42%), HEXA (2/113, 1.77%), TUBB4A (2, 1.77%), and ALDH3A2, POLR3A, FA2H, ERCC2, BCKDHB. One chromosome 18q terminal deletion has also been found. [Conclusion] PMD caused by PLP1 mutation is the most commonly seen disease among HLDs. Developmental delay and abnormal brain MRI manifestations are essential for diagnosis. Among all HLD patients clinically diagnosed, 113/124 (91.13%) have been detected molecular genetic change. This study is the first large scale clinical and genetic analysis of Chinese HLD patients and may provide useful information for clinical diagnosis, genetic consulting prenatal diagnosis of HLD patients.